The type of reservoir that is of interest herein is best described in U.S. Pat. No. 6,389,757 issued to C. J. DeGarie on May 21, 2002. This document describes an industrial clarifier that has a flexible membrane-type cover mounted thereon. The cover is supported over a reservoir by a series of arched pipes spanning across the reservoir. When access inside the reservoir is needed, for maintenance of equipment inside the reservoir for example, the cover is rolled up on a mandrel to one side of the reservoir. The rolling up of the cover on a mandrel is done by hand; by hand crank, or by using a powered tool connected to the end of the mandrel. A spool of cover material is formed by winding the fabric over the mandrel while the mandrel is rolled across the reservoir.
In order to ensure the safety of workers, a handrail and a kick plate are required around the perimeter of the reservoir. The presence of these handrails makes it difficult to wind up the cover, by hand or by using a hand crank. It will be appreciated that the winding of the cover must be interrupted at every post supporting the transverse handrails. Such interruption in the winding motion is required to allow one's arms to reach over every post supporting the handrails. When a power tool is used, the tool must be stopped and disconnected from the mandrel, and reconnected past every post supporting the handrails.
Therefore, there is a need in the field of reservoirs for a better installation so that a cover can be wound up in one stride across a reservoir, while maintaining the safety of the personnel working around the reservoir.